<template>
  <div class="upload-file">
    <!-- 上传按钮 -->
    <el-upload
      multiple
      :action="uploadFileUrl"
      :before-upload="handleBeforeUpload"
      :file-list="fileList"
      :limit="limit"
      :on-error="handleUploadError"
      :on-exceed="handleExceed"
      :on-success="handleUploadSuccess"
      :show-file-list="false"
      :headers="headers"
      class="upload-file-uploader"
      ref="fileUpload"
    >
      <el-button type="primary" icon="Upload">选取文件</el-button>
    </el-upload>
    <!-- 上传提示 -->
    <div v-if="isShowTip" class="el-upload__tip">
      请上传大小不超过 <b>{{ fileSize }} MB </b>格式为 <b> {{ fileType.join('/') }} </b> 的文件
    </div>
    <!-- 文件列表 -->
    <transition-group class="upload-file-list el-upload-list" name="el-fade-in-linear" tag="ul">
      <li :key="file.uid" class="el-upload-list__item" v-for="(file, index) in fileList">
        <a :href="file.url" target="_blank">{{ getFileName(file.name) }}</a>
        <el-button v-if="flag" type="danger" icon="Delete" circle @click="handleDelete(index)" />
      </li>
    </transition-group>
  </div>
</template>

<script setup>
import { getToken } from '@/utils/auth'
// 接收 绑定值, 文件数量, 文件类型, 提示
const props = defineProps({
  modelValue: [String, Object, Array],
  flag: {
    type: Boolean,
    default: true
  },
  limit: {
    type: Number,
    default: 5
  },
  fileSize: {
    type: Number,
    default: 5
  },
  fileType: {
    type: Array,
    default: () => ['doc', 'xls', 'ppt', 'docx', 'xlsx', 'pdf', 'text', 'png']
  },
  isShowTip: {
    type: Boolean,
    default: true
  }
})
// 上传文件的url和header
const uploadFileUrl = ref(import.meta.env.VITE_APP_BASE_API + '/file/upload')
const headers = ref({ Authorization: 'Bearer ' + getToken() })

const { proxy } = getCurrentInstance()
const emit = defineEmits(['update:modelValue'])
const number = ref(0)
const uploadList = ref([])
const fileList = ref([])

watch(
  () => props.modelValue,
  (val) => {
    if (val) {
      let temp = 1
      // 首先将值转为数组
      const list = Array.isArray(val) ? val : props.modelValue.split(',')
      // 然后将数组转为对象数组
      fileList.value = list.map((item) => {
        if (typeof item === 'string') {
          item = { name: item, url: item }
        }
        item.uid = item.uid || new Date().getTime() + temp++
        return item
      })
    } else {
      fileList.value = []
      return []
    }
  },
  { deep: true, immediate: true }
)

// 上传前校检格式和大小
function handleBeforeUpload(file) {
  // 校检文件类型
  if (props.fileType.length) {
    const fileName = file.name.split('.')
    const fileExt = fileName[fileName.length - 1]
    const isTypeOk = props.fileType.indexOf(fileExt) >= 0
    if (!isTypeOk) {
      proxy.$modal.msgError(`文件格式不正确, 请上传${props.fileType.join('/')}格式文件!`)
      return false
    }
  }
  // 校检文件大小
  if (props.fileSize) {
    const isLt = file.size / 1024 / 1024 < props.fileSize
    if (!isLt) {
      proxy.$modal.msgError(`上传文件大小不能超过 ${props.fileSize} MB!`)
      return false
    }
  }
  proxy.$modal.loading('正在上传文件，请稍候...')
  number.value++
  return true
}

// 文件个数超出
function handleExceed() {
  proxy.$modal.msgError(`上传文件数量不能超过 ${props.limit} 个!`)
}

// 上传失败
function handleUploadError() {
  proxy.$modal.msgError('上传文件失败')
}

// 上传成功回调
function handleUploadSuccess(res, file) {
  if (res.code === 200) {
    uploadList.value.push({ name: res.data.name, url: res.data.url })
    uploadedSuccessfully()
  } else {
    number.value--
    proxy.$modal.closeLoading()
    proxy.$modal.msgError(res.msg)
    proxy.$refs.fileUpload.handleRemove(file)
    uploadedSuccessfully()
  }
}

// 删除文件
function handleDelete(index) {
  fileList.value.splice(index, 1)
  emit('update:modelValue', listToString(fileList.value))
}

// 上传结束处理
function uploadedSuccessfully() {
  if (number.value > 0 && uploadList.value.length === number.value) {
    fileList.value = fileList.value.filter((f) => f.url !== undefined).concat(uploadList.value)
    uploadList.value = []
    number.value = 0
    emit('update:modelValue', listToString(fileList.value))
    proxy.$modal.closeLoading()
  }
}

// 获取文件名称
function getFileName(name) {
  if (name.lastIndexOf('/') > -1) {
    return name.slice(name.lastIndexOf('/') + 1)
  } else {
    return ''
  }
}

// 对象转成指定字符串分隔
function listToString(list, separator) {
  let strs = ''
  separator = separator || ','
  for (const i in list) {
    if (list[i].url) {
      strs += list[i].url + separator
    }
  }
  return strs !== '' ? strs.substr(0, strs.length - 1) : ''
}
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.el-upload__tip {
  b {
    color: #f56c6c;
  }
}
.upload-file-list {
  .el-upload-list__item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f1f2f4;
    padding: 0.05rem 0.1rem;
    margin-bottom: 10px;
  }
}
</style>
